Method of making comb members for dry shavers



0. HORRER pril 11, 1944.

METHOD OF MAKING COMB MEMBERS FOR DRY SHAVERS Filed May 8, 1941 0 O O OO O O 0 00000000 000000000 0 0000000 00000000 00000000 00000000 000000000000000 00000000 000000000 0 0%. 0 0 0 0 0 o o nwo owv o o o 000000000000000 00000000 000000000 0000000 00000000 00000000 000000000 000000000000000 00000000 000000000 0000000 00000000 00000000 000000000 000000000000000 00000000 000000000 0000000 00000000 00000000 000000000 0 GROUND.0005" 0 Patented Apr. 11, 1944 METHOD OF MAKING COIMB MEMBERS FOR DRYSHAVERS Otto Horrer, Chicago, 111., assignor to Chicago Flexible ShaftCompany, Chicago, 111., a corporation of Illinois Application May 8,1941, Serial No. 392,417

Claims. (Cl. 76- -104) This invention relates to the manufacture of acomb member for a dry shaver, particularly the thin perforated plate orcomb member of the type shown in Patent No. 2,234,891.

In the commercial manufacture of comb structures of the kind disclosedin said patent certain structural irregularities occurred in thefinished comb member, the observance of which was not readily apparentand the presence of which impaired the cutting efficiency. Furthermore,this condition necessitated a grinding operation requiring the removalof a relatively large amount of stock, considering the nature of theoperation, which not only added to the cost but tended to make for othervariables in shape characteristics of the comb member. This presented aserious problem, particularly in view of the small and somewhat delicatestructure of the perforated comb body, the hardness of the metal and thehigh degree of precision desired in the finished product.

The main object of the present invention is to provide a simple andpracticable solution of this problem.

Another object of the invention is to provide an improved method ofmaking a comb member of the character described with a view to re- Fig.2 i a cross section taken on the section,

line 2--2 of Fig. 1;

Fig. 3 shows the strip flexed to a curved form, as a diagrammaticillustration;

Fig. 4 shows the step of passing the strip between opposed rollers withthe strip in section;

Fig. 5 is a fragmentary view looking at one end of the parts shown inFig. 4: V

Fig. 6 is a fragmentary section illustrating the roller actionapproximately ten times full size and being diagrammatic insofar asconcerns "deformation of the comb member between the bite of therollers;

Fig. 7 is a section through the comb member similar to Fig. 2 after therolling operation;

Fig, 8 is a cross section through a shaving implement showing anapplication of the comb member, with the' parts approximately four timesfull size; and

Fig. 9 i a cross-section through a comb member showing diagrammaticallythe effect after the rolling operation and before flexing the comb, asdescribed hereinatfer.

The comb member to which my invention applies is of the type andmanufacture shown in Patents Nos. 2,234,891- and 2,182,067. The combmember here designated generally by H constitutes the skin-engagingmember of a shaving implement which member is provided withhairreceiving openings and constitutes the stationary cutting member,the cutting edges being at the inner side, that is, the side oppositefrom the skin-engaging side. This comb member is preferably of thinspring steel in the nature of razor blade steel and in the preferredmanufacture the hair-receiving openings are formed by a punchingoperation, although they may be otherwise formed in keeping withthepresent invention. The said openings or perforations may be of anysuitable or preferred shape and arrangement, and in the presentembodiment I have shown, for purpose of illustration, a relativeiy largenumber of small round openings it closely positioned in a given medialarea. This embodiment may also include elongated openings l3 shaped toprovide opposed rows of teeth M. The small openings I2 are adapted forclose shaving'and the teeth H for clipping long hairs.

The openings l5 are relief openings for egress of the cut hair. This orany other combination of openings may be employed in keeping with thepresent invention.

-The comb member H may be applied to a shaving implement in any suitableor preferred manner, the well known application being shown in the abovementioned patents and here illustrated briefly in Fig. 8. This shows themember supported by a rigid skeleton frame structure designatedgenerally by 16 having longitudinal members I! joined by a plurality ofarched ribs Hi, to which frame structure the finished comb member issecured, preferably in the manner disclosed in Patents Nos. 2,234,893and 2,234,929. The comb structure comprising the member II and itssupporting frame 16 as a unit is-detachably held in working position byreleasable, members IS. A cutter 2| coacts with the-inner side of thecomb member H and is adapted to be rapidly oscillated in a cuttingstroke'by means of a holder,22 operated in a well known manner by anelectric motor or any suitable source of power.

In actual practice the comb member is of spring steel in sheet formapproximately .004" thick and having a Rockwell hardness of 50. In theparticular embodiment shown the first step in the manufacture is topunch the perforations l5 and then grind the surface area defined by theborderline 23 to approximately .002" thickness. This grinding is donewith the strip supported on a suitable fixture, it being immaterialwhether the area being ground is supported on a flat or a curvedsurface. The strip is then punched to form the perforations i2 and 13above mentioned, thus leaving imperforate marginal areas 24. Theopenings 25 are incidental for the purpose of attaching the blank to afixture (not shown) on which the blank is held during the abovementioned grinding operation. According to the prior practice the blankwas then flexed, as shown in Fig. 3, approximately to the curvature itwas intended to occupy in coaction with the cutter, as shown in Fig. 8,and while in this condition the inner surface of the comb was ground orlapped preferably by a cylindrical rotary abrasive member as covered byPatent No. 2,182,067. Following the grinding operation under "the priorpractice the end portions of the blank'were cut off as indicated at 26and openings 21 were punched for the reception of rivet heads forattaching the comb member to a supporting frame as disclosed in theabove mentioned patents. .In order to lap the entire innersurface of the.comb member it was necessary, prior to my invention, to grind off aconsiderable amount of stock, particularly at the heavier end portions,frequently to the extent of removing as much as .'0015=,,-this being acomparatively expensive operation considering the hardness of the stock,the area, and the high degree of precision desired.

My invention provides'f'or aspecialforming operation-prior to thegrinding or lapping .of the inner side of the blank, whereby the'innersurfaces of the several perforated areas of the blank are broughtapproximately to a straight line along any line longitudinally when *thecomb member is flexed to thecurvature it will-occupy in the shaver, andas a consequence thereof the .in-

ner side may be ground or lapped "quickly and satisfactorily by removalof 'not'more than about .0003" of material." Furthermore, this methodtends to leave the perforated areas free from irregularities,distortions or'an'y'bulge effect in the extremely thin portion when thecomb member is in the curved, operative condition, thus improving thecutting efiiciency. "In the'preferred practice of my invention thisspecial operation consists in effecting a small degree of uniformelongation of the heavier section of the blank along the ends thereof,the effectof which is to set-up such compression stresses in thesemarginala're'a's as to cause "them-to assume a slightly upturned anglewith relation to the blank pr-ope'r when the blank is fiat '(as showndiagrammatically in Fig. 9) and a relation substantially in a straightline with the intermediate body of the'comb member along any linelongitudinally thereof when 'it' is in the curved, operative condition(as shown in Fig. '7). This is effected preferably by passing the blankendwise between apair of steel'rollers 28 and constructed and arrangedto'impose a high compression at the bite, sulhcient to effect the slightuniform elongation .of the metal contemplated by my invention. As shownin Fig. 4, thelower roller 28 has a truly cylindrical. face while theupper roller 29 has-a similar face which is ground to provideshallowgrooves 32'of not more than .0005" depth arranged oppositetheperforated areas l3 so that the teeth l4 and the narrow imperforatestrip at the inner side thereof will be relieved from the full rollerpressure. As a result of this operation the reduction in thickness ofthe blank at the marginal edges is so slight as to be negligible, thatis, hardly susceptible of measurement, but a new result is obtained inthe form of the blank as a whole, in that because of the slightelongation of the marginal areas the several portions of the comb memberare brought into a new shape relation in which the said marginal areasare slightly turned up with respect to the remainder of the blank. Thislatter effect is merely incidental to the compression stresses set up inthe marginal areas as a result of the rolling operation. Thus, when theblank is curved in the opposite direction to the desired curvature theseveral areas assume a condition of stress wherein the entire undersurface of the blank is in substantially a straight line longitudinallyof the curved surface at every point, that is, the underside of theextremely thin section is .in a straight line with the underside of theheavier marginal sections, as shown in Fig. 7. The rolling operationtakes place after the blank has been perforated and before the grindingor lapping and preferably before trimming off the end portions at thelines 26. Figs. 2 and 3 show somewhat exaggerated the bulged orirregular condition of the extremely thin portion of the blank beforethe rolling operation, the dotted line in Fig. 3 indicating extension ofthe extremely thin section beyond the thicker end portions. In theseviews the extent of the bulge is exaggerated for the purpose ofillustration.

Likewise, in Fig. 6 the depth of the roller relief is exaggerated andthe view is intended to be diagrammatic since in actual practice thereis no resultant reduction in thickness of the stock so far as isnoticeable to the eye or by ordinary measurement. By reason of theroller relief at 32 the narrow marginal portions of the comb memberengaged thereby willbe subjected to less pressure than the outermarginal portions 24 so that there will not be excessive elongation ofthe narrow marginal sections. This roller relief is also arranged so asnot to impose the heavy pressure on the small teeth I t, thus'protectingthe small teeth from fracture and breakage.

The results of my invention are particularly beneficial not only becauseof the saving in time and abrasive material in the grinding operation,

but in obtaining a more uniform product in keeping with the high degreeof precision desired for the respective parts. For example, by re-.ducing the grinding or lapping to the small degree above noted thethickness of the end portions and consequently of the teeth M is keptuniform and the extremely thin area 23 is substantially relieved fromobjectionable compression stresses when in the curved operativecondition. As a result of this method of manufacture more eiiicientcoaction is obtained between the comb II and the cutter 22 and thecutting action is improved. My invention may be practiced either with orwithout perforations such as [3. My invention also contemplates broadlythe step of effecting slight elongation of the marginal areas for thepurpose described by the use of any equivalent means for this purpose.

While I have shown a particular embodiment of my invention, it will beunderstood that I do not wish to be limited thereto since manymodifications may be made, and I therefore contemplate by the appendedclaims to cover any such modifications as fall within the true spiritand scope of my invention.

I claim:

1. The method of making a comb member for a dry shaver, from a strip ofthin spring steel, including the step of reducing the thickness of thestrip in a given central area by grinding, the step of providinghair-receiving openings in said area by perforating the same, and thestep of uniformly elongating the marginal portions only of the stripwhich are located at opposite edges thereof beyond said reducedperforated area, said elongation being efiected throughout the length ofsaid marginal portions and being of sufficient degree to cause the saidmarginal portions to assume a slightly upturned angle with relation tothe strip proper when the strip is fiat.

2. The method set forth in claim 1, in which said elongation of saidmarginal portions is effected by passing the strip between opposed highpressure rollers, one of which has a central area of reduced diameterlocated opposite the reduced central area of the strip.

3. The method set forth in claim 1, in which said reduction by grindingis effected only at one side of the strip, and in which said elongationof said marginal portions is effected by passing the strip betweenopposed high pressure rollers, one of which has a cylindrical surfaceengaging the non-reduced side of the strip and the other haslongitudinally spaced cylindrical surfaces en gaging said marginalportions and also has a central area of reduced diameter locatedopposite the reduced area of the strip so as to relieve the reducedperforated area of the strip from direct pressure of the rollers.

4. The method of making a comb for a dry shaver, from a strip of thinspring steel, including the step of reducing the thickness of a centralportion of the strip by grinding and leaving marginal portions ofheavier section, punching hair-receiving openings in said centralportion and a row of teeth in each marginal portion at opposite ends ofsaid central portion, leaving imperforate the marginal edge portion ofthe strip at the outer side of each row of teeth, and passing the stripbetween rollers which subject only said marginal edge portions to highroller pressure to effect uniform elongation of said marginal edgeportions throughout the length thereof.

5. The method of making a comb for a dry shaver, from a strip of thinspring steel of approximately 004" thickness, including the step ofreducing the thickness of a central portion of the strip by grinding toapproximately .002" and leaving marginal portions of heavier section,punching closely spaced hair-receiving openings in said central portionand a row of teeth in each marginal portion at opposite ends of saidcentral portion, leaving imperforate the marginal edge portion of thestrip at the outer side of each row of teeth, and passing the stripbetween rollers which subiect only said marginal edge portions to highroller pressure to effect uniform elongation of said marginal edgeportions throughout the length thereof.

OTTO HORRER.

